Understanding UK peatlands

JNCC and a wide partnership of bodies have commissioned research
into the Greenhouse Gas and carbon (C) fluxes associated with UK
peatlands. Two research reports (No's. 442 and 443) are now
available reviewing the existing evidence for peatland emissions,
and another report provides improved knowledge of peatland
types, their distribution and status.

Peatland ecosystems are important habitats recognised under
international and national legislation. As well as having
unique biodiversity, over time natural peatlands can capture and
store carbon, removing greenhouse gasses (GHGs) from the
atmosphere. Carbon is laid down in the form of partially
decomposed plant and animal remains, as decay is limited by
waterlogged conditions. Over the past 10,000 years, UK
peatlands have sequestered around 5.5 billion tonnes of carbon from
the atmosphere, which dwarfs the 150 million tonnes stored in our
woodlands. Peatlands therefore contain over half the ~10
billion tonnes of carbon stored in UK soil.

Undamaged peatlands accumulate carbon in peat material much
faster than it is naturally lost. However, human activities
can alter the balance between accumulation and loss, turning the
peatland into a source of carbon. Peatland ecosystems have
been extensively degraded in recent times through a variety of
activities, such as drainage and cultivation. Many of these
processes lower the water level, producing more aerobic conditions,
which encourages decomposition and rapid release of greenhouse
gases (GHGs) to the atmosphere. These activities can also increase
the amount of dissolved or suspended carbon lost to adjacent water
bodies and represent significant environmental concerns.

Efforts to restore damaged UK peatlands are increasing with a
focus on restoring the natural waterlogged conditions, usually for
biodiversity, archaeological and hydrological reasons.
However, re-wetting peat produces methane (CH4), which
is a considerably more powerful greenhouse gas than CO2,
and the short to medium-term effects of restoration on the GHG flux
from peatland is poorly understood. Restoration aimed at conserving
or enhancing carbon stocks and mitigating climate change may
require different approaches to biodiversity restoration which
have, until recently, been secondary or low priority aims.

With recognition of the effects of climate change and the UK
entering its second carbon budget period, the ecosystem services
provided by peatlands for regulating carbon stocks have become
increasingly important to understand. Long-term restoration
could produce a significant reduction in UK carbon emissions, but a
greater understanding of the GHG effects of different management
strategies is needed for peats to contribute effectively to the
UK’s carbon reporting. The extent of peatlands under
different management regimes and the amount of GHG/carbon that is
stored or lost under these needs to be confirmed. This will
allow the production of emission factors to quantify the GHG/carbon
flux. The same information will support practical
decisions about how to manage peatlands for maximum benefits for
all interests – from biodiversity to climate change mitigation.